如果我们将Deque声明为允许来自双方的输入和输出的一般方法，那么技术错误是什么？

We know that a Deque has two sub category... Input restricted and output restricted... Now what is the technical error in designing a Deque in such a way that it has no restrictions i.e. The user can enter and remove data from both the front and back at any time ...with any restrictions !!!We know that a Deque has two sub category... In